Prelude:
I just picked one up when I decided to get a VLocity JR as the JR's programming just plain sucks stock.... By sucks, I mean NON-EXISTENT. Fairly simple fix, just had to get a new chip. I had heard of the Gangstar Chip from Claustrophobia, and decided that it might be a safe bet as it was only $30. I bought mine from a user on PBN that wasn't going to use it and was NIB. If you can't find a deal on PBN, you can buy them from the manufacture's website: GangstarPaintball.
Installation:
When I first opened the envelope, I was fairly unimpressed by the simple black container and simple looking chip inside with a sticker on it that said "Gangstar." I opened up my VLocity JR the next day when it came in, and undid the board from the shells so I could reach the stock chip. I yanked mine out with a knife and a pair of needle nose and promptly tossed it in the trashcan. I figured that if the Gangstar didn't work, I'd merely sell it and get another chip as there are a bunch of them out there. I plopped the Gangstar chip in fairly easily (Make sure and note where the recessed dot is on the top of the stock chip, and put the dot on the Gangstar in the same spot, as that denotes the first pin), and closed my VLocity JR all back up, installing a Speedfeed.

Review:
I turned it on to see what it could do over a drop test and was instantly amazed at the difference. I didn't record the time as I didn't have a clock near me, but it was damn quick. Definitely faster than the stock chip, and without that damned annoying pulsing noise it had! I downloaded the manual to see what else it could do, seen here. After reading it, I decided to go into the programming mode (very easy to get into as well), and set it to my preferred settings (full force, speed 10, tension 8, breakout mode 3). Turned it off, turned it back on, and it was definitely working very well. I took it out on my Cyborg to see how well it performed on gun, and after shooting a couple pods of paint through at 20bps, I was certainly pleased with it's performance. Even with trying to make my shots choppy to test it's consistency, I couldn't get it to screw up. The only break I had the entire time was a barrel break on a bad ball.

Overall/TL;DR:
If you have a VLocity and aren't satisfied, pull out that damned stock chip and put this in, I highly recommend it!

Scores:
Installation: 5, easy as pie!
Adjusting: 4, a little tricky until you get the hang of it.
Use: 5! This thing rocks!